For the vermin extermination, various methods have been developed so far. In particular, termites cause enormous damage to wooden houses, and therefore, extermination agents and extermination methods of vermin have been researched and developed in the world. The methods for exterminating termites include a method of injecting a solution agent such as an organophosphorus agent, a carbamate agent, or a pyrethroid agent into invasion places to kill the insects, or a method of performing smoking by methyl bromide or the like to kill the insects (see, for example, Non-patent Document 1).
As an alternative method of a method of spraying an agent, there is bait method in which a slow-acting insecticidal active ingredient is mixed in a bait and the bait is fed to termites and thereby exterminating the termites (see, for example, Non-patent Document 2).
Conventional extermination techniques are basically to throw an agent in large quantity from the outside of the damaged wood to kill the insect. However these techniques lead to health damage such as sick building syndrome or to environmental pollution. Moreover, there is a problem that if some of colonies of termites remain, the damage is made to spread to another place. The most serious problem is that the labor cost required for the extermination is too much. Fumigation techniques using methyl bromide have been frequently carried out, however methyl bromide is a causative substance of the ozone layer destruction, and in recent years, trend of trying to regulate the use of methyl bromide has increased.
As an effective method for exterminating ants which organize a social life in the same manner as in termites, there is a method of mixing a favorite food of ants into a poison and providing the mixed food as a bait to allow the ants to bring the food to their nests and killing the entire population of the ants. However, because termites eat the wood itself in which the nest is built, the bait method for allowing the termites to convey an agent from the outside of the nest to the inside of the nest by using a poison bait is not always effective. In particular, it is difficult to eradicate the nest of Reticulitermes speratus by the bait method (see, Non-patent Document 2).
As a method for making vermin to ingest active ingredients more efficiently than bait method, “a method for exterminating vermin by conveyance of mimetic eggs” has been developed (Patent document 1) in which egg conveyance instinct that is basic social behavior of the vermin is utilized. The vermin in this method were termites. However, in this method, it has been possible to make termites to convey mimetic eggs by using crude extracted ingredients extracted from eggs of termites, however the egg recognition pheromone has not been identified. Unless the egg recognition pheromone is identified and can be produced largely and inexpensively, there has been a large problem of the cost for carrying out such a method.
In particular, if the vermin are termites, the extermination is difficult by the reason described below, and a conclusive solution has not been found yet.
Because termites make their habitat in a closed space, in a wood, it is difficult to infiltrate an agent from the outside.
Because the termites organize social lives, if some of colonies remain, the termites move and make the damage expanded.
Because termites live by eating the wood itself in which they make their habitat, introduction of a poison bait is not effective.
Patent document 1: JP 2000-342149 A
Non-patent Document 1: “Termites and strategies of extermination”, The Japan Termite Control Association, 2000, p. 219
Non-patent Document 2: “Activity evaluation of Japanese underground termites using a monitoring station and the extermination by bait methods”, New developments of monitoring technique of insect ecology in a living zone, 2006, p. 48